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name: tailing-build-output description: Monitor a build process (webpack, turbo, docker) for warnings and errors as they stream. Summarize issues and fix them before the build finishes. user-invocable: true

Tailing Build Output

Watch a build process in real time via terminal files and fix issues as they appear.

Workflow

1. Start or Find the Build

Either start the build yourself or find the terminal running it:

head -n 10 <terminals_folder>/*.txt

Look for commands like npm run build, pnpm build, turbo build, docker build, tsc, vite build.

2. Poll for Output

Read the terminal file periodically. Look for:

Errors (fix immediately):

• ERROR / Error: / error TS
• Module not found / Cannot find module
• SyntaxError / TypeError
• Failed to compile

Warnings (collect for summary):

• WARNING / Warning: / warn
• Deprecation / deprecated
• Unused imports/variables
• Large bundle size warnings (asset size limit)

Progress indicators:

• Webpack: [XX%], modules, chunks
• Turbo: task completion logs
• Docker: Step X/Y
• TypeScript: file count

3. Fix Errors in Flight

When an error appears:

1. Extract the file path and line number from the error
2. Read and fix the source file
3. If the build supports watch mode, it will re-trigger automatically
4. If not, note the fix and let the build continue — it may reveal more errors

4. Summary Report

After the build completes (check for exit_code in terminal footer):

Build Summary:
  Status: Failed (exit code 1) / Succeeded
  Duration: ~45s
  Errors fixed: 3
  Remaining warnings: 2
    - Large bundle: src/pages/Dashboard.tsx (450kb)
    - Deprecated API: useRouter from 'next/router'

Tips

• Don't fix warnings during the build — collect them and address after
• For turbo build, errors may appear in parallel task output — check all task logs
• Docker builds cache layers — if you fix a file early in the Dockerfile, later layers rerun
• TypeScript's --noEmit is useful for type-checking without a full build